Disconnect switch

ABSTRACT

An improved electrical disconnect switch of the scissors type whose counter contact is fastened to a rigid current rail. The counter contact is formed by at least one pair of spaced vertically extending resilient finger-type contacts and the contact for the scissors mechanism is formed by a horizontally disposed contact bolt which is rigidly fastened to one of the arms of the scissors-type switch at the upper scissors joint thereof and extends from at least one side of the upper scissors joint in a direction parallel to the pivot axis of the joint.

United States Patent [191 Paal [45 1 Feb. 12, 1974 DISCONNECT SWITCH [75] lnventor Felix Paal,Niederkaufungen,

Germany [73] Assignee: Licentia Patent-Verwaltungs G.m.b.H., Frankfurt am Main, Germany [22] Filed: Apr. 3, 1972 [21] Appl. No.: 240,624

[30] Foreign Application Priority Data Apr. 1, 1971 Germany.... 2115901 Apr. 1, 1971 Germany 7112539 [52] US. Cl 200/48 V [51] Int. Cl. H01h 31/00 [58] Field of Search 200/48 R, 48 V [56] References Cited UNITED STATES PATENTS 3,009,995 11/1961 Turgeon 200/48 V 3,530,265 9/1970 Albright 200/48 V Primary Examiner-Herman J. Hohauser Attorney, Agent, or Firm-Spencer & Kaye 571 ABSTRACT An improved electrical disconnect switch of the scissorstype whose counter contact is fastened to a rigid current rail. The counter contact is formed by at least one pair of spaced vertically extending resilient fingertype contacts and the contact for the scissors mechanism is formed by a horizontally disposed contact bolt which is rigidly fastened to one of the arms of the scissors-type switch at the upper scissors joint thereof and extends from at least one side of the upper scissors joint in a direction parallel to the pivot axis of the joint.

6 Claims, 2 Drawing Figures 1 DISCONNECT SWITCH BACKGROUND OF THE INVENTION which is shown for example in German Patent No.

1,081,103, does not permit a particularly low or short structural height for the switching system since in the switched-off position the ends of the arms which extend beyond the upper scissors joint with their spacing from the countercontact determine the length of the switching path. The situation is similar with scissors-type disconnect switches which bear a contact piece extending beyond the upper scissors joint, e.g. see Austrian Patent No. 191,977.

In addition to the above-mentioned drawback relating to the height of the switching system of the prior art scissors-type disconnect switches, it is known in the art that for switches of a high current handling capability, it is desirable for the contact area of the switch contacts to be cleaned during the switching process, i.e. the opening and closing process, by rubbing the contact pieces against one another. This rubbing process, however, is eliminated for a scissors-type disconnect switch with vise-type contact pieces.

SUMMARY OF THE INVENTION 7 The above-mentioned drawbacks and problems presented by the prior art scissors-type disconnect switches are solved according to the present invention in that the countercontact for the switch, which countercontact is fastened to a rigid current rail disposed above the switch, is provided in the form of one or more pairs of spaced vertically extending resilient finger-type contacts, and the switch contact is provided in the form of a horizontally disposed contact bolt which is rigidly fastened to one of the arms of the scissors at the upper scissors joint for the arms and which extends from at least one side of the upper scissors joint parallel to the pivot axis thereof.

According to the preferred embodiment of the invention two such contact bars are provided, each attached to a respective one of the scissors arms, and extending in opposite directions from the upper scissors joint, and each engaging at least one pair of resilient finger-type contacts.

The preferred embodiment of the scissors-type disconnect switch according to the invention has the ad vantage that the contact pieces, i.e. the contact bar, do not protrude beyond the upper scissors joint so that the shortest possible distance between the scissors and countercontact is provided in the switched-off or open state of the switch. The two contact bolts always perform a vertical movement when thescissors are moved while they maintain their horizontal position. Additionally each of the contact bolts experiences a rotating movement when the switch closes and opens in addition to the sliding movement in the countercontact since the scissor arms are rotated, thus producing a particularly good cleaning of'the contact surfaces. The rotating of the contact bolts also has a considerable icebreaking effect during opening of the switch, should the switch contacts be iced up when it is switched on or closed. The contact bolts further permit the provision of a plurality of transfer points for the current at the finger-type countercontact, which may for example be U-shaped since a larger number of finger contacts can be provided.

The finger-type contacts may be self-resilient or may be additionally supported by an external spring, e.g. a leaf spring, so that thecontacts themselves can experience larger current charges. The dissipation of heat in this arrangement is mainly effected by the external spring.

According to a further embodiment of the present invention the finger-type contacts are fastened to resilient flat rods which are disposed in parallel to the cur rent rail and fastened thereto. This makes it possible to still further reduce the structural height of the switching system and thus reduce, in particular, its construction costs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates one embodiment of the scissorstype disconnect switch according to the invention with the scissors thereof in engagement with the countercontact.

FIG. 2 shows a particularly advantageous alternate embodiment of the countercontact.

DESCRIPTION OF THE PREFERRED EMBODIMENTS I As shown in FIG. 1, the scissors-type disconnect switch has a housing 1 which is disposed on a supporting strut (not shown).

Mounted on the housing 1 for movement relative thereto is a scissors mechanism having lower arms 2, 2' and upper arms 3, 3. The housing 1 accomodates the gear mechanism coupledwith the lower scissors arms 2, 2 and, if required, a weight compensation element for the scissors mechanism. The gear mechanism is actuated via a rotary isolator (not shown) which is connected with the end of shaft 4.

At the level of the upper scissors joint 9, contact bolts 5 and 5 are rigidly fastened to the: scissors arms 3 and 3' respectively. The bolts 5 and 5' are fastened to the arms 3 and 3' so that they are horizontally disposed and extend from the opposite sides of the joint 9 parallel to the pivot axis thereof. Preferably as illustrated they extend along the pivot axis of joint 9. It is to be understood however, that although the invention has been illustrated with two separate contactbolts 5 and 5 that a single contact bolt rigidly connected to only one of the arms and extending along the pivot axis of joint 9 may also be used.

Mounted above the housing 1 and arranged so that they will engage the contact bolts 5 and 5' are pairs of vertically disposed resilient finger-type contacts 6 and 6, respectively, which form two U-shaped countercontacts. These countercontacts are welded to the rigid current rail 7 or are fastened thereto in some other way. When the switch is switched on and off, the contact bolts 5 and 5 perform a sliding as well as a re tary movement between finger contacts 6, 6, so that the contact surface is well cleaned and no significant contact resistances can be produced. This fact, together with the possibility of being able to provide a larger number of current transfer points, i.e. pairs of finger-type contacts 6 or 6, leads to a high current capability for the disconnect switch.

The switched-off or open position of the switch, which is shown in dashed lines, shows that the contact system does not protrude beyond the scissors at this point so that the counter-contact can be attached at a lower point than with the known scissors-type switches while still providing the same length of switching path.

In the illustration of FIG. 2 the finger-type contacts 6 and 6 are supported at the ends of resilient flat rods 8 and 8 respectively which are fastened to and disposed parallel with the current rail 7. This type of countercontact permits even greater reduction of the structural height of the circuit breaker.

In order to improve the current handling capability of the illustrated switch, the resilient finger-type contacts may be additionally supported by an external spring, e.g. a leaf spring, which will not only provide a stronger contact pressure but moreover will serve for the dissipation of heat at the contacts.

It will be understood that the above des cription of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

I claim:

1. In a scissors-type electrical disconnect switch having a movable contact and a countercontact which is fastened to a rigid current rail disposed above the movable contact the improvement wherein the movable contact of said switch comprises a horizontally disposed contact bolt rigidly fastened to one of the scissors arms of said switch at the upper scissors joint thereof, and extending from one side of said upper joint in a direction which is parallel to the pivot axis thereof, and said countercontact includes at least one pair of spaced vertically extending resilient finger-type contacts.

2. The scissors-type disconnect switch defined in claim 1 wherein at least two pairs of said resilient finger-type contacts are provided; and further including a further one of said horizontally disposed contact bolts rigidly connected to the other of the scissors arms at said upper scissors joint and extending from the opposite side thereof.

3. The scissors-type disconnect switch defined in claim 1 wherein said contact bolt extends from both sides of said upper scissors joint and wherein said countercontact includes at least two pair of said finger-type contacts.

4. The scissors-type disconnect switch defined in claim 2 wherein said finger contacts are self-resilient.

5. The scissors-type disconnect switch defined in claim 2 wherein said finger-type contacts are fastened to resilient, fiat rods which are fastened to said current rail and are disposed parallel thereto.

6. The scissors-type disconnect switch defined in claim 2 wherein said contact bolt extends along said 

1. In a scissors-type electrical disconnect switch having a movable contact and a countercontact which is fastened to a rigid current rail disposed above the movable contact the improvement wherein the movable contact of said switch comprises a horizontally disposed contact bolt rigidly fastened to one of the scissors arms of said switch at the upper scissors joint thereof, and extending from one side of said upper joint in a direction which is parallel to the pivot axis thereof, and said countercontact includes at least one pair of spaced vertically extending resilient finger-type contacts.
 2. The scissors-type disconnect switch defined in claim 1 wherein at least two pairs of said resilient finger-type contacts are provided; and further including a further one of said horizontally disposed contact bolts rigidly connected to the other of the scissors arms at said upper scissors joint and extending from the opposite side thereof.
 3. The scissors-type disconnect switch defined in claim 1 wherein said contact bolt extends from both sides of said upper scissors joint and wherein said countercontact includes at least two pair of said finger-type contacts.
 4. The scissors-type disconnect switch defined in claim 2 wherein said finger contacts are self-resilient.
 5. The scissors-type disconnect switch defined in claim 2 wherein said finger-type contacts are fastened to resilient, flat rods which are fastened to said current rail and are disposed parallel thereto.
 6. The scissors-type disconnect switch defined in claim 2 wherein said contact bolt extends along said pivot axis. 